The bill at a restaurant came to $136.40.The customer decided to leave a 15% tip. What was the total bill including tip.

$156.86

Step-by-step explanation:

To calculate tip, you need to multiply the total bill by the percent tip you are going to leave. In this case the bill is $136.40, and the customer is going to leave a 15% tip. So, you would want to move the decimal place over to the left by 1, which you should get 13.64 as your number. Then divide it in half, which should give you 6.82. Now add 13.64 and 6.82 with the original bill price. If you don't add the 13.64 you would've forgotten the 10% part of the tip. At the end you should get $156.86 as your final bill.

since your problem is x^4 = 81, what you have to undeo is the "to the fourth power" part.

the inverse (opposite operation) of "to the fourth power" is "to the fourth root".

  (x^4) ^ ¼   = 81 ^ ¼  

  81 = 3^4     so (3 ^ 4) ^ ¼   =   3 ^ 1   = 3

by hand: (3 ^ 4) ^ ¼   =   3 ^ (4 x ¼) = 3 ^ 1   = 3   (when you take a power to a power, multiply the exponents.)

or, do it by calculator. one way of finding the fourth root is to use ^ (1/4)

step-by-step explanation: